DEX based fighter is certainly a viable option.
1 thing that people should keep in mind however is that heavy armor has a STR requirement. You could use medium armor at a pinch but some of the endgame heavy armors wouldnt be an option if you keep your STR to low.
Dex fighters don't generally want to use heavy armors though, because heavy armors don't allow dex bonus to AC. With a dex of 20 (+5), Studded Leather is as good as Splint. Better actually, because less weight and no disadvantage on stealth checks. The highest-level heavy armor is Plate, which only adds +1 AC compared to the above, so not
that much of a difference.
Also, plate armor isn't an end-game armor. It's a mid game at most, and really should be available to players at level 4-5 (Larian fix this please; give us more heavy armors). End-game armors are magical versions of normal armors, and +3 studded leather should be equally as find-able as +3 plate.
